In the field of construction machines, several-hundred-ton class, extra-large heavy machines, such extra-large hydraulic excavators, are operating throughout the world for earth excavation in a large mine. It is demanded that these extra-large heavy machines operate continuously in order to improve productivity in ore mining. An operation data collection device is mounted in the extra-large heavy machines to collect detailed operation data for the purpose of preventing a failure that obstructs such continuous operations.
A hydraulic fluid cooling system failure diagnostic device for construction machines that is described in Patent Document 1 permits anyone to readily identify the cause of an overheat without the experience and skill of a service technician when, for instance, hydraulic fluid is overheated in a hydraulic fluid cooling system for operating a heavy machine. The hydraulic fluid cooling system failure diagnostic device performs constant monitoring by way of comparing specific sensor data received from the heavy machine against a determination threshold value. Whenever the sensor data is outside a normal range, the hydraulic fluid cooling system failure diagnostic device records the sensor data and a plurality of other relevant sensor data.